Adding on to Albatross's reply ...

Silver, as Alby notes, the takeout is the takeout (except for Canada, which has a monopoly system and takes a surcharge from Canadian bettors holding winning tickets at US tracks, similar to how NYCOTB used to work).

The "host track" (in this case, Oaklawn) charges a "signal fee" for all the action that comes in from Twin Spires, NYRA, etc (the non-Arky entities that probably account for 95% of Oaklawn's handle). Those entities take the bets, pay Oaklawn their signal fee (a % of handle), pay their various taxes, and take their profit.

Oaklawn gets their "signal fee" % (whatever that is ... say it's 10% on all bets) on that 95% of handle, or, $1.9 million (10% x $20MM x 95%), plus say they get a blended 20% of the million in Arky handle. So they get $2.1 million for covering their purses and expenses.

I'm not strong on this stuff. Happy to be corrected by anyone who knows better. Hard to know what the signal fees are, as these things are not public knowledge and are closely held. But as a general rule, the more desirable the product, the higher the signal fee.